 | This article may be too technical for most readers to understand. (April 2018) |
| Condensed matter physics |
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In physics, polaritons /pəˈlærɪtɒnz, poʊ-/[1] are bosonic quasiparticles resulting from strong coupling of electromagnetic waves (photon) with an electric or magnetic dipole-carrying excitation (state) of solid or liquid matter (such as a phonon, plasmon, or an exciton).[example needed] Polaritons describe the crossing of the dispersion of light with any interacting resonance.
They are an expression of level repulsion (quantum phenomenon), also known as the avoided crossing principle. To this extent polaritons can be thought of as the new normal modes of a given material or structure arising from the strong coupling of the bare modes, which are the photon and the dipolar oscillation. Bosonic quasiparticles are distinct from polarons (fermionic quasiparticle), which is an electron plus an attached phonon cloud.
Polaritons violate the weak coupling limit and the associated photons do not propagate freely in crystals. Instead, propagation speed depends strongly on the frequency of the photon.
Significant experimental results on various aspects of exciton-polaritons have been gained in the case of copper(I) oxide.
- ^ "Polariton". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 2021-01-17.